NEW QUESTIONS!! Need help on electrical system please!

Mon Nov 12, 2012 10:52 pm

Hello everyone, you have an awesome site here! I recently acquired a cub, sn 113978, a 48 model I believe. It belonged to my uncle and he used to take my daughter for rides on it since the time she was 2months old up untill she was 6 when he passed. She would laugh so hard her sides would hurt! He always ntended to "fix it up" as he would say but never got to it. Needless to say we both have fond memories of the them on the cub. She is now 13 and Has always wanted to restore the tractor in honor of my uncle and we were finally able to acquire it from my cousin and now we have a project on our hands. She is active in 4H and intends to use it as a 4H project so we intend to restore to original. So here is the first of many many questions!,It needs a new wiring harness badly but which one, 4 or 8 wire? Someone has made a total mess of the wiring and none of the original harness is left. luckily it will still start and run.I know I have a 6v system with a generator where the neg cable goes to the starter. It has a push n pull on off switch and a 4 pos rotary dial for charging and lights but not sure if it works because lights don't come on and there is no change in the ammeter when you go from low to high charge setting. Also, it seems to crank really slow even though the battery is hot.Not sure how to tell what system I have, magneto or no mag, voltage reg or no voltage reg, etc etc?I just don't know enough about this old stuff to feel confident in ordering the correct electrical stuff. Someone Please help and thanks in advance.....

Last edited by Jdbfish on Tue Nov 13, 2012 11:26 pm, edited 1 time in total.

Re: Need help on electrical system please!

Mon Nov 12, 2012 11:08 pm

If it is a 48 and has a 4 position switch, it should have a cutout, not a voltage regulator. If the harness is in bad shape, I would start with a complete rewire (schematics on this site), and service the generator and cutout. Then if it still isnt charging, while i had the hood off, i would begin troubleshooting with the generator flow chart (also avaiable on this site). Good luck with it, and Im sure Rudi will be along soon with the welcome wagon!

Re: Need help on electrical system please!

Mon Nov 12, 2012 11:11 pm

G'day to you and congrats on acquiring your first new to you 1950 Farmall Cub Yup SN 113978 equates to a 1950 - you can check it here at Cub FAQ's #1 on ATIS - #13. I am glad that both you and your daughter have such a close and personal connection to this Cub and that you are going to do this project together.

Might I suggest that before either of you do anything to your Cub that you thoroughly read the McCormick Farmall Cub Owner's Manual 1950. After you have read the manual a couple times and are familiar with the Cub - pay attention to Lubrication and Maintenance. As you will find out your Cub has a Magneto and a positive ground system.

The ignition circuit is separate from the electrical circuit. The only part that the battery plays is to power the starter. Otherwise you would have to hand crank the Cub to start it. A full tune-up would be in order before you get too deeply into the Cub. Make sure that everything works as it should before you start the restore. That way you will know for sure that everything is ok and if something doesn't perform properly after the restore, you will have a place to start the troubleshooting from - that being a known runner. Suggest you follow the links below as it will help both you and your daughter and especially your daughter as she uses this for her 4-H project.

Re: Need help on electrical system please!

Mon Nov 12, 2012 11:46 pm

Don't forget to check for original signs of WHITE paint under the hood and in places that might have gotten "missed" during a RED re-paint. White paint was only used on Dealer DEMONSTRATER tractors, and they were produced ONLY the first few months of 1950 (3 months I think). Yours is a 1950, so I would check that too! That would add to the "coolness" of the project!

Re: Need help on electrical system please!

Tue Nov 13, 2012 12:56 am

That serial number is, as already stated, 1950. It is well past the time the white demos were built, so don't expect to find any white paint. It is also well before the change to battery ignition and voltage regulators. As built, it had a cut-out (also called relay) type system. The cut-out mounted on top of the generator. The first two positions of the light switch manually controlled the charge rate. It had magneto ignition. The ignition switch grounded out the magneto to shut the engine off. There was no connection between the ignition system and any other electrical components. The wiring harness had 4 wires.

Re: Need help on electrical system please!

Re: Need help on electrical system please!

Tue Nov 13, 2012 8:29 am

The diagrams should also be in the op manual (any manual).

In my option a new harness is a smart investment. Once you sort out exactly what you have, get the right one. Mag and cutout are the things that make a difference. My 50 has a regulator, but I could tell by the tach hole in the distributor base it was converted somewhere along the line.

Brillman has very nice complete wiring packages and is very good to deal with. You can also get it from a dealer (C&G, link on the bottom of this page) or aftermarket ones.

Re: Need help on electrical system please!

Tue Nov 13, 2012 11:23 pm

Ok guys, thanks for all the replies. I pretty sure I have a cutout because there is a box on the generator with 3 posts total, 2 on bottom and 1 on top. It is hard to read but I can tell it says delco remy on it. The starter also says delco. With that NGO can anyone tell me the following please:

1. Which wiring harness do I need2. What tune up kit or parts do I need to do a complete tune up including plug wires. 3. Although not electrical related, what carb kit do I need

Please give me part numbers and descriptions if possible. I apologize for my ignorance here and thank all of you for the help

Re: NEW QUESTIONS!! Need help on electrical system please!

Use an IH kit for the carb, but make sure you need to do it first and know what you are doing before you split it and break the fragile tube inside.

See TM tractor in the links below for tune up parts or browse Brillman above.

Re: NEW QUESTIONS!! Need help on electrical system please!

Wed Nov 14, 2012 6:55 am

In addition to all the advice already given, TM tractor has an impressive collection of photos, which will help you identify the various components on your Cub. While you're there, they are a first rate supplier of Cub parts, as well as a supporter of this site, you'll do well to do business with them.

Re: NEW QUESTIONS!! Need help on electrical system please!

Wed Nov 14, 2012 8:24 am

And Welcome to the Forum

Re: NEW QUESTIONS!! Need help on electrical system please!

Wed Nov 14, 2012 9:20 am

Welcome to the forum.

I would give the carb a good cleaning before I purchased a kit. Like Bob said be careful when you take the 2 halves apart as not to break the tube. Take a small piece of stiff wire and run it into all the small openings and soak it in some carb cleaner for a little while. I like to take my air conpressor and blow everything out. When you put it back together make sure the carburetor gasket and the intake gasket is good.